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The Differences Between Sudden Death Syndrome and Brown Stem Rot

September 16, 2021
sudden death syndrome infects soybean plant

Sudden Death Syndrome in Valmeyer, IL; 2019.

By late summer, soybeans are well into the reproductive growth stage, with pods and beans developing. At this time, 2 similar-looking soybean diseases may appear in fields: Sudden Death Syndrome (or SDS, causal organism Fusarium virguliforme) and Brown Stem Rot (or BSR, causal organism Cadophora gregata).

Early planting – associated with cool, wet weather – typically increases both SDS and BSR root infection potential, and symptoms of both diseases that appear later in the season can be similar, including premature reduction in leaf canopy and an associated drop in yield potential.

Do you suspect SDS or BSR is in your field? Here’s how to tell:

While both diseases come from early-season root infection, the main symptoms that develop during the later reproductive growth stages are different. Dig several suspected plants and carefully split the lower primary plant stem above the soil line.

  • SDS infection: The central portion of the stem – the pith – should remain clean and white, like a normal, healthy plant. Later in the season, the leaf tissue between the veins will yellow and die. Eventually, the yellowed, dead leaf material will drop off, leaving only the petiole (the small leaf stem that attaches the leaflet to the main plant stem) attached to the main plant stem.
  • BSR infection: The pith will be discolored, thus the common name Brown Stem Rot.

Left: SDS; Right: BSR. Images courtesy of Dr. Dean Malvick, professor of Plant Pathology, University of Minnesota.

Currently, no seed treatment solutions for BSR exist, and genetic packages for protection against SDS and BSR are often not provided in the same soybean varieties. If you do have SDS in your field, we recommend upgrading your protection to Saltro® fungicide seed treatment. With more power than older technology, Saltro delivers consistently superior SDS protection without the stress, helping soybeans maximize their full genetic yield potential.

For more information about Saltro, speak to your retailer or visit WhySaltro.com.

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Product performance assumes disease presence.